The cost of motor oil seems unrelated to the cost of gasoline, even though they are both made from oil.
Probably 10 years ago, it was not unusual for local auto stores to have sales on cases of oil along with a mail in rebate program. With both the sale and the rebate, you could get oil for less than $1 per quart. And gas prices were still around $2.50-$2.75 per gallon. Then all of a sudden, motor oil prices skyrocketed and companies discontinued their rebate programs, and the prices haven't fluctuated hardly at all compared to gas prices.
So no, I don't think we'll see motor oil prices come down.
And in my opinion, you won't see gas prices stay this low for long. Something will give: OPEC will restrict volume, or American production will decrease because they cannot produce profitably at such low prices. Either way, prices will go up, and probably WAY up. Again, just my opinion.